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Re: DINOSAUR digest 3468 (Oviraptors=Parrots?)



Hi all
I don't know if it's been mentionned before but egg-crushing is not the only
way to open an egg. I can easily see an animal the size of "Oviraptor" could
pierce the egg just with its beak and hence having it open, without crushing
it in its jaws. Sounds easy. I don't know nothing about dinosaur's eggshall
thickness  (when alive) but I'm sure if it could be broken by a baby dino
from the inside, there was no problem for a, somewhat, bigger adult from the
outside. This involves no strong biomechanics or muscle-ry(?) in any way.
Egg-crushing theory isn't everything. There are many ways to peel a panther
(Conan the Barbarian)
Cheers,
Jean-Michel


----- Original Message -----
From: "Jaime A. Headden" <qilongia@yahoo.com>
To: <dinosaur@usc.edu>
Cc: <jorgedich@yahoo.com>
Sent: Sunday, February 05, 2006 1:59 AM
Subject: Re: DINOSAUR digest 3468 (Oviraptors=Parrots?)


> Jorge Dichenberg (jorgedich@yahoo.com) wrote:
>
> <Animal the size of Oviraptor could break any eggshell without special
> adaptations.>
>
>   An animal the size of *Oviraptor* had an eight inch skull, not a
behemoth
> contraption of steel and iron. This was bone, made from thin struts with
large
> apses between them, and while it had attachments for large muscle and the
space
> to accomodate them, the function of the jaws in a biomechanical sense is
far
> from explained.
>
> <Nice, so predator theory is falling.>
>
>   Who said this? I was describing a semi-narrative about the way the
evidence
> was arrived at and the reasons others doubted previous data. Since Norell
et
> al. have not described any data that costradicts Barsbold, they have used
other
> data to suggest an alternate, or combined, mode.
>
> <Many birds are vegetarian as adults but feed animal food to nestlings.>
>
>   We have no evidence oviraptorids ate plants.
>
> <For example, many finches and sparrows are seed-eaters, but bring insects
to
> nest. Asian hornbills are fruit-eaters, but succesfully hunt small animals
to
> feed chicks.>
>
>   Hornbills also successfuly feed on tiny mammals and lizards to feed
> themselves, and will even use them to profer food to potential mates.
>
> <If oviraptorids could manipulate food with their hands, it would
compensate
> for akinetic skull.>
>
>   How manipulative would hands be if they only faced in one direction and
could
> only extend and fold in one way? Given also that oviraptorids have a small
> skull on a long and slender neck with more vertebrae than the typical
theropod,
> one can reasonably suggest the hands were unneccesary for rotating eggs or
> lizards or such. But they seem ideal, rather, for grasping prey. And by
prey, I
> mean animals much larger than your average lizard. Also don't forget that
> oviraptorids probably had tongues which, like in parrots, could have been
> manipulative.
>
> <Every seed must fall to the ground to germinate. So, unless there was a
niche
> of seed-eating pterosaurs, oviraptorids could feed on ground or with
limited
> climbing.>
>
>   How many seed plants available in these formations? Enough to sustain or
> supplement the diet of all oviraptorids within the area? Don't forget that
> there were plenty of lizards and mammals that may have been seed-eaters,
> including the seemingly well-adapted multituberculates, which possess the
> overhanging shearing incisors and broad, multicupsed and low-crowned
molars of
> seed-eaters.
>
> <I always thought it is not phylogeny-related, but common to long-billed
birds
> with short tongues. No need for throwing food if you have beak so short as
> parrot or oviraptorid.>
>
>   It is possible that for some birds, the long snout may have evolved for
the
> purpose of drinking and feeding on tiny prey. Note that hydrostatic
pressure
> allows the bird to dip only the tip of the beak into the water in passing
to
> drink, as the pressure of the water drops forces it to adhere the the
beak's
> surface as the bird opens its jaws, bringing the water into the mouth.
> Oviraptorids are way to large to make use of this, but I wouldn't put it
past
> them to use suction and lapping like most animals (including large birds!)
> their size.
>
> <But now seed-eating seems more plausible.>
>
>   But what seed-eating adaptations and what seeds are available enough to
drive
> the evolution of a skull so derived from any typical, long-snouted and
toothy
> ancestor?
>
>   Cheers,
>
> Jaime A. Headden
>
> "Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)
>
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